Canada-Approved Medicine

This monograph describes a medication approved for use in Canada by the Therapeutic Products Directorate, a division of Health Canada’s Health Products and Food Branch. The medication is not approved by the United States Food and Drug Administration; however, a similar formulation carrying a different generic or brand name might be available in the US.

• Subcutaneous injection: Initial and maintenance palliative treatment of advanced hormone-dependent prostate cancer (usually given with an anti-androgen).
• Nasal solution: Maintenance palliative treatment of advanced hormone-dependent prostate cancer (usually given with an anti-androgen).
• Nasal solution: Nonsurgical treatment of endometriosis (course of treatment 6–9 mo).

Contraindicated in:

• Hypersensitivity
• Nonhormonal-dependent prostate cancer or previous orchiectomy
• Females with undiagnosed vaginal bleeding
• OB: Pregnancy (avoid use)
• Lactation: Avoid breastfeeding (small amounts enter breast milk; injection contains benzyl alcohol).

Use Cautiously in:

• Prostate cancer with urinary tract obstruction or spinal lesions
• Pedi: Safety and effectiveness not established (injection contains benzyl alcohol).

CNS: depression, dizziness.

CV: hypertension.

Endo: glucose intolerance.

Hemat: anemia.

Local: injection site reactions.

MS: osteoporosis (long-term use).
Misc: transient exacerbation of metastatic prostate cancer or endometriosis.

Prostate cancer

CNS: headache (nasal solution).

EENT: nasal irritation (nasal spray).

GU: ↓ libido, impotence.

Derm: hot flushes.

Endo: gynecomastia, testosterone flare.

MS: bone pain.

Endometriosis

CNS: headache, weakness, insomnia.

CV: edema.

GI: constipation, gastrointestinal disorders, nausea.

GU: ↓ libido, vaginal dryness, menorrhagia.

Derm: hot flushes, acne.

Endo: suppression of ovulation.

MS: back pain.

Drug-Drug:

• Risk of serious arrhythmias may be ↑ by concurrent amiodarone, disopyramide, dofetilide, flecainide ibutilide, propafenone quinidine, sotalol, antipsychotics (including chlorpromazine) antidepressants (including amitriptyline and nortriptyline), opioids (including methadone), macrolide anti-infectives (including azithromycin, erythromycin and clarithromycin), fluoroquinolones (including moxifloxacin), azole antifungals, 5-HT3 antagonists (including ondansetron), beta-2 receptor agonists (including salbutamol), pentamidine, and quinine.

• Solution for subcutaneous injection (contains benzyl alcohol): 1000 mcg/mL;
• Intranasal Solution: 1000 mcg/mL (delivers 100 mcg per actuation);

Prostate cancer

• SC (Adults): Initial treatment: 500 mcg every 8 hr for 7 days, Maintenance treatment: 200 mcg daily.
• Intranasal (Adults): Maintenance treatment: 400 mcg (200 mcg in each nostril) 3 times daily.

Endometriosis

• Intranasal (Adults): 400 mcg (200 mcg in each nostril) 3 times daily. Treatment is usually continued for 6 mo; not to exceed 9 mo.

• Acts as a synthetic analog of endogenous gonadotropin-releasing hormone (GnRH/LHRH). Chronic use results in inhibited secretion of gonadotropin release and gonadal steroid production. The overall effect is due to down-regulation of pituitary LHRH receptors. In males, testosterone synthesis and release is decreased. In females, secretion of estrogen is decreased.

• Decreased spread of advanced prostate cancer.
• Decreased sequelae of endometriosis (pain, dysmenorrhea).

Therapeutic Classification: antineoplastics, hormones

Pharmacologic Classification: luteinizing hormone-releasing hormone (LHRH) analogues

Absorption: SUBQ: 70%; intranasal: 1–3%; implant: drug is slowly absorbed over 2–3 mo.

Distribution: Accumulates in liver, kidneys and anterior pituitary lobe; enters breast milk in small amounts.

Metabolism/Excretion: Metabolized in liver, kidneys and by enzymes on membranes in the pituitary gland.

Half-life: SUBQ: 80 min; intranasal: 1–2 hr; implant: 20–30 days.

Suprefact

†↓ in testosterone levels.

‡Symptom improvement.

• Inform male patients that they may experience breast swelling and tenderness, decreased libido, hot flashes and sweats, impotence and weight gain. Notify health care professional if these symptoms occur.
• Inform female patients that they may experience decreased libido, constipation, painful sexual intercourse, menopausal symptoms, changes in hair growth. Notify health care professional if these symptoms occur.
• Caution both male and female patients to use contraception while taking this drug. Advise females of reproductive potential to inform health care professional if pregnancy is suspected. Buserelin may cause fetal harm.
• SC: Instruct patient in proper technique for self-injection, care and disposal of equipment. Use only syringes included in kit. Instruct patients that syringes may only be used once, and then discarded.
• Intranasal: Instruct patient on proper nasal spray technique. Prime pump before use.
• Advise patients that the nasal spray can cause nose bleeds, and may change smell and taste senses.

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